This has been Philip Rivers’ worst year — up to Thursday’s romp over Kansas City, when other than one awful decision he was brilliant, as good as a QB can get. But my guess is there’s nothing wrong with Rivers better protection wouldn’t cure. When he has time, he’s very good. But he should stop throwing on the run — except out of bounds. He can’t do it.

Running backs

C+

Ryan Mathews really is a good runner — when he doesn’t leave the ball on the floor (which isn’t as often as thought). Norv has to use him more, because he adds danger. Third-down back Ronnie Brown has his legs under him now and is proving to be a fine, all-around acquisition. And Jackie Battle will do in a pinch.

Receivers

D

Antonio Gates may have lost a step but there still are times when he can’t be covered. Robert Meachem and Eddie Royal basically have done nothing. I said the offense would be better with transient, untried subs Danario Alexander and Seyi Ajirotutu and, for once, I wasn’t wrong.

Offensive line

D

A strange group. For some reason, it’s much better at run blocking than protecting the passer. It’s usually the other way around. It’s better, no question, when Jared Gaither plays, although he, like Rivers, at times is prone to brain flatulence. Louis Vasquez could become a monster at right guard but needs to be more consistent.

Defensive line

C

This is a young, improving group, which is a good thing, in that this has been a weakness. Much stouter against the run than its predecessors. There is some depth here, which allows fresh rotation. Corey Liuget is doing what a young, high-draft choice should be doing — getting better.

Linebackers

B-

It’s official now. Donald Butler is one of the better inside linebackers in the league. Shaun Phillips still can make a play. But for whatever reason — maybe it’s just not cut out for it — the front seven has trouble reaching the passer. Unless there’s improvement, a continuance will hurt the team in the second half.

Secondary

D+

Eric Weddle is a terrific player, one of the best free safeties in The League, although he hasn’t made the plays he made last year. This whole group hasn’t. There just aren’t enough takeaways and the problem with third-down stops — as we saw against lowly K.C. — hasn’t been corrected.

Special teams

A-

Coach Rich Bisaccia has resurrected teams. Mike Scifres simply is a brilliant punter, one of the best ever. Nick Novak, taking over for the departed Nate Kaeding, has yet to miss a field goal. Coverage is outstanding. Only problem is in the return game, where there is little danger — especially now with Richard Goodman out and Royal injured.

Coaching

C

The team is 4-4, .500. C. Norv still makes you scratch your head sometimes, but he hasn’t lost the locker room, that’s for sure. His guys play for him, it’s just that they don’t often play well for him — especially for 60 minutes. A simpler approach with a lot of new players may not challenge Turner’s intellect, but it may help win games. I like John Pagano. The defense attacks more now. But there must be a pass rush.

General manager

C-

A.J. Smith had his busiest offseason in a decade as GM and his free agent acquisitions certainly made a splash. But not much has come out of it. Receivers Meachem and Royal have been mediocre at best. Linebacker Jarret Johnson is solid, as are the aforementioned Brown and Battle. The draft has yet to play out but it holds promise. It’s also not impossible that all the new guys will play better.